Temperature control device



Nov. 14, 1939. L. L. YOUNG TEMPERATURE CONTROL DEVICE Filed April 28,19:58

INVENTOR. LLOYD L. YOU/VG ATTORNEY.

Patented Nov. 14, 1939 PATENT V OF'FlCE TUBE OONTBOL DEVICE Lloyd L.Young, Patchogne, N. Y., assignor Radio Corporation of America, acorporation ofDelawarc Application April as, 1938, Serial No. 204,912;.12 Claims. (01. 219-38) This invention relates to a new and novelmethod of temperature control and deals specifically with a device forthe control of self-contained heat generation and/or control of electriccurrent for any purpose.

An object of this invention is to simplify and- A further object of thisinvention is to provide I ll smooth temperature regulation to suchdevices as a piezo-electric crystal employed for accurate control offrequency in a radio circuit.

The features of this invention are based upon the principle ofArchimedes as illustrated by the well known Cartesian devil" and alsoupon the principle of Faraday's law of electro-magnetic induction. I

This invention is particularly directed to two forms, one form in whichthe heat is generated by Foucault currents, or eddy currents, the otherform being arranged such that heat is generated by electric currentsflowing through high' resista'nce conductors.

In the prior art practice, the current generating heat in highresistance conductors was gen- I erally controlled by means of contactelectrodes with or without complicated vacuum tube circuits and alsoemployed mechanicai'electro-magnetic relays or mercury circuit breakers.By my invention, all such circuit breakers and contact electrodes areeliminated. Furthermore, the use of all thermostats or like devices isdispensed with, thus materially reducing the cost of the temperaturecontrol system. A feature of this invention is that it provides a smoothcontinuous regulation instead of in steps, as many of the prior artdevices.

Another feature of this invention is that it may be used as a pressureregulator.

This invention may best be understood by referring to the accompanyi gdrawing, in which:

l lg.lisanctiopthm ahasimpleformof tcmperaturecontrcldflm;

mJaisaplanvilwofl lgi; 5o m.2isanothermcdlflation gsgornblyoi Fig.1; and

. plgflisanotherunbodlmantinwhichthedw viceis'surroundedbytwowindings.neferringnowindetailtomlandlmaninsulatingcontainerlisprovidedwitharemovofthe floating able cover 2, theunder portion of which may be provided to retain a suitable oven orcontainer 3, within which may be located a piezo-electric crystal holder(not shown) or any other device in which the temperature is desired tobe maintained substantially constant, suitable electric connectionsbeing made to the device whose temperature is to be controlled by meansof leads I and 5.

Within casing l is located a fluid 6 such as, for example, alight gradeof oil or any other suitable material. Surrounding the lower portion ofinsulating casing l is a coil winding 1 which is arranged for setting upastrong magnetic field by being connected to a suitable source ofalternating current voltage 8. Located approximately withinthe centralportion of the casing, a Cartesian devil 9 is secured by means of finethreads I, which prevent the floating assembly from touching the sidesof the container, but permit ample freedom of vertical movement. Withinelement 9 there is maintained an air pocket I l which responds tochanges in temperature and pressure by volume changes. Member 9 isweighted down by a plurality of weights I! which are in the form ofcontinuous metallic ring-like conductors, the number and size beingmaintained such'that the displaced oil nearly balances the weight of.member 9. An opening l3, which is closed by means of a threaded stud l4,permits inspection of the oil level and its replenishment whennecessary.

In the operation of i is cold,the air in the buoyancy of element I0 isdecreased so that the floating element 9, with the associated rings I2,sinks and the flve threads Ill suspend the floating element 8 inside ofthe coil I. When power is applied to coil I, a strong field of magneticilux is set up around the shorted turns l2, causing large currents toflow which, because of the resistance in the shorted turns 12, generates heat, thus heating the oil 8. When the oil becomes sufllcientlyheated and the air within chamber II is warmed, the air expands, perthisdevice, when the liquid mitting the float 9 to rise gradually, leavingthe zone of the strong magnetic field. As the float causes the turns I!to recede from the magnetic fleld, the currents in rings I! becomesmaller and by the process of slow hunting," the float S will come atrest to a point where the fleld strength is just enough to inducecurrents in shorted conductor l2, which generates suflicient heat as isdissipated, so that the temperature of theoilisthenmaintainedconstantispace H is contracted and a with reference to Fig. I, except that theheat is generated in the metal shell I5, by eddy currents set up in theshell by the alternating magnetic fleld from the winding I, which inthis case is energized by alternating currents of suitable frequency.

Referring now to Fig. 3, part of the heat is produced by means of eddycurrents occurring in a shell l6 which is'preterably composed ofmagnetic material acting as a booster heater, andpart by the heaterresistance member H which is enersized by a secondary winding I 8 whichforms part ora transformer, having an external core or cup 19 and cover2|, which aids in theoperation oi the device. The operation of Fig. 3 issuch that when the float 9 is in the lower. position, the shell I6 is insuch a position that the strong magnetic flux i'rom coil I threads orcuts the turns of coil it, strongly inducing a current to flow. causinga decrease in 'the reluctance of the magnetic circuit. As floatingelement O'rlseathe magnetic material of i6 is withdrawn from the fleldand the flux is not so strong through and around coil .II, so that theheating current in i1 is decreased. The float 8 will then seek aposition of rest as in the cases, of the devices described in Figs. 1and 2, wherein the heat generated just equals the heat dissipated andthe temperature of the device becomes substantially constant. Theapplication of these devices may vary. as, for instance, if the currentin coil ll of 1"18. 3 is passed through a meter (not shown) it may becalibrated to read in terms of temperature. Various devices requiringclose and smooth temperature control may utilize the devicesoi thisinven-: tion. Also, another application of a device similar to that ofFig. 3 is that there is-connected in i the circuit of soil It a relay,polarized so that a pressure pump may be controlled .as, for example,in'a refrigerator. 4

There are various other modifications that could be made in the abovedevices. such as causing movement of the float II to make and break theelectrical circuits; also, to change the reluctance in a magneticcircuit. Therefore, this invention should not be limited;to the .precisedevices shown.

What is claimed is:

, 1. A temperature control device comprising an insulating casing, acoil surrounding said casing, a liquid whose temperature is maintainedconstant within said casing, a floating element in said liquid, aringlike medium member. secured .tosaid floating element, and means forpassing an alternating current. through said coil whereby eddy currentsset up by said ring-like member heat said liquid to a desired constanttemperature.

.2. A temperature control device comprising an insulating casing, a coilsurrounding said casing, an oil-like liquid within said casing, afloating element in said liquid, a ring-like metallic' meniber securedto said floating element, and means for passing an alternatingcurrentthrough said coil whereby eddy currents set up by said ringlikemember heat said liquid to a desired constant temperature.

3. A temperature control device comprising an insulating casing, a coilsurrounding said casin a liquid whose temperature is maintained constantwithin said'casing, a floating element having a space filled with airthe volume of which changes with the temperature of said liquid, a

' ring-like metallic member secured to said floating element, and meansfor passing an alternatingcurrent through said coil whereby eddycurrents set up by said ring-like member heat said liquid to a desiredconstant temperature.

4. A temperature control device comprising an insulating casing, a coilsurrounding said casing, a liquid whose temperature is maintainedconstant within said casing,a floating element in said liquid, a metalshell member secured to said floating element, and means for passing, analternating current through saidicoil whereby eddy currents set up bysaid metal shell me'mber heat said liquid to a desired constanttemperature. 5. A temperature control device comprising an insulatingcasing, a coil surrounding saidcasing, a liquid. whose temperature ismaintained-constant within said casing, a floating element in saidliquid, a metal shell of magnetic material secured to said floatingelement, and means ior passing 6. A temperature control devicecomprising aninsulating casing, a coil surrounding said casing,

a liquid'whose temperature is maintained constant within said casing, afloating element in said liquid, a long narrow metallic shell ofmagneticmaterial secured to said floating element, and means for passingan alternating current through said coil whereby eddy currents set up by.said metallic shell heat said liquid to desired constant temperature.

floating element in said liquid, a ringlike metallic member secured tosaid floating element, and means for passing. an alternating currentthrough at least oneoi-said coils whereby eddy currents set up by saidring-like metallic member heat said liquid to a desired constanttemperature. 1

.7. A, temperature control device comprising.-

8. A temperature control device comprising an insulating casing, aplurality of coils surrounding said casing, a heating coil locatedwithin said casing and connected to a=source' 01 power, a a

liquidwithin said casing, a floating element in I said liquid, aring-like metallic membersecure'd to. said floating element, means forpassing alternating current through at elast one of said coils wherebyeddy currents are set up by said metallic member causing heat liquid ata desired temperature. I 9. A temperature control device comprising aninsulating casing,- a coil surrounding said casing,

a liquidwhose temperature is maintained c0n-" stant within said casing,a piezo-electric crystal which maintainssaid element surrounded by saidliquid, a floating element in said liquid, a ring-like metallic membersecured to said floating element, and means for passing an alternatingcurrent to said coil whereby eddy currents set up by said ring-likemember heat said liquid to a desired constant temperature.

10. A temperature control-device comprising an insulating casing havinga cover, a piezo-electric crystal secured to said cover, a liquid whosetemperature is to be maintained constant within said casing, a floatingelement in said liquid, a ringlike metallic member secured to saidfloating element, and means for passing an alternating current throughsaid coll whereby eddy currents set up by said ring-like member heatsaid liquid to a desired constant temperature.

11. A temperature control device comprising an insulating casing, atransformer having a core and a plurality of coils surrounding saidcasing, a heating coil located within said casing and connected to oneof the coils of said transformer, a liquid within said casing, afloating element in said liquid, 2. ring-like metallic member secured tosaid floating element, means for passing an alternating current throughat least one of said coils whereby eddy currents are set up by saidmetallic member causing heat which maintains said liquid at a desiredtemperature.

12. A temperature controlling device comprising a container filled withliquid, a body having a gas filled space floating in said liquid, amember adapted to have heating currents induced therein carried by saidbody, and means relatively fixed in position with respect to saidcontainer inducing currents in said member whereby the induced currentsflowing in said member cause heating of said liquid thereby changing thevolume of gas in said body and thereby causing said body to float to aposition such that the heat generated by said member substantiallyequals the heat dissipated by the liquid.

LLOYD L. YOUNG.

